(1) Field of the Invention
This invention relates to a passive seat belt system, and more specifically to a passive seat belt system provided with a rigid holding means at one end portion of a guide rail.
(2) Description of the Prior Art
Passive seat belt systems have been known, which are of such a type that an occupant is automatically restrained upon riding a motor vehicle in order to assure the safety of the occupant in case of an emergency of the vehicle.
In a passive seat belt system of the above type, a slide anchor carrying a buckle, which is latched with a tongue fastened to one end of an occupant-restraining webbing and is releasable in case of an emergency, is caused to move back and forth along the length of the vehicle, on a guide rail and along the roof side of a vehicle, whereby the webbing is brought close to and away from an associated occupant seat so as to form a room sufficient to allow an occupant to get on and off the motor vehicle and also to apply the webbing automatically to the occupant after he has sat in the seat.
The slide anchor is movable freely between both ends of the guide rail. The rigidity of the guide rail is lower at both ends (front and rear ends) thereof compared with its rigidity at its intermediate portion. Further, the buckle may undergo substantial displacements, namely, may swing in the direction of the width of the vehicle while the passive seat belt system is in use
Such undue swinging of the buckle has a potential danger such that an associated interior trimming may be lifted off or damaged and the guide rail may be damaged or deformed. A damage to the guide rail or its deformation may result in a poor operation of the passive seat belt.
To cope with this potential problem, it may be contemplated to enlarge the dimensions of the guide rail itself so that its rigidity is improved. This approach is however difficult to practise since pillars are designed narrower in recent motor vehicles.